Imported Debian version 2.5.3~trusty1
[deb_ffmpeg.git] / ffmpeg / libavcodec / vmdaudio.c
1 /*
2 * Sierra VMD audio decoder
3 * Copyright (c) 2004 The FFmpeg Project
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 /**
23 * @file
24 * Sierra VMD audio decoder
25 * by Vladimir "VAG" Gneushev (vagsoft at mail.ru)
26 * for more information on the Sierra VMD format, visit:
27 * http://www.pcisys.net/~melanson/codecs/
28 *
29 * The audio decoder, expects each encoded data
30 * chunk to be prepended with the appropriate 16-byte frame information
31 * record from the VMD file. It does not require the 0x330-byte VMD file
32 * header, but it does need the audio setup parameters passed in through
33 * normal libavcodec API means.
34 */
35
36 #include <string.h>
37
38 #include "libavutil/avassert.h"
39 #include "libavutil/channel_layout.h"
40 #include "libavutil/common.h"
41 #include "libavutil/intreadwrite.h"
42
43 #include "avcodec.h"
44 #include "internal.h"
45
46 #define BLOCK_TYPE_AUDIO 1
47 #define BLOCK_TYPE_INITIAL 2
48 #define BLOCK_TYPE_SILENCE 3
49
50 typedef struct VmdAudioContext {
51 int out_bps;
52 int chunk_size;
53 } VmdAudioContext;
54
55 static const uint16_t vmdaudio_table[128] = {
56 0x000, 0x008, 0x010, 0x020, 0x030, 0x040, 0x050, 0x060, 0x070, 0x080,
57 0x090, 0x0A0, 0x0B0, 0x0C0, 0x0D0, 0x0E0, 0x0F0, 0x100, 0x110, 0x120,
58 0x130, 0x140, 0x150, 0x160, 0x170, 0x180, 0x190, 0x1A0, 0x1B0, 0x1C0,
59 0x1D0, 0x1E0, 0x1F0, 0x200, 0x208, 0x210, 0x218, 0x220, 0x228, 0x230,
60 0x238, 0x240, 0x248, 0x250, 0x258, 0x260, 0x268, 0x270, 0x278, 0x280,
61 0x288, 0x290, 0x298, 0x2A0, 0x2A8, 0x2B0, 0x2B8, 0x2C0, 0x2C8, 0x2D0,
62 0x2D8, 0x2E0, 0x2E8, 0x2F0, 0x2F8, 0x300, 0x308, 0x310, 0x318, 0x320,
63 0x328, 0x330, 0x338, 0x340, 0x348, 0x350, 0x358, 0x360, 0x368, 0x370,
64 0x378, 0x380, 0x388, 0x390, 0x398, 0x3A0, 0x3A8, 0x3B0, 0x3B8, 0x3C0,
65 0x3C8, 0x3D0, 0x3D8, 0x3E0, 0x3E8, 0x3F0, 0x3F8, 0x400, 0x440, 0x480,
66 0x4C0, 0x500, 0x540, 0x580, 0x5C0, 0x600, 0x640, 0x680, 0x6C0, 0x700,
67 0x740, 0x780, 0x7C0, 0x800, 0x900, 0xA00, 0xB00, 0xC00, 0xD00, 0xE00,
68 0xF00, 0x1000, 0x1400, 0x1800, 0x1C00, 0x2000, 0x3000, 0x4000
69 };
70
71 static av_cold int vmdaudio_decode_init(AVCodecContext *avctx)
72 {
73 VmdAudioContext *s = avctx->priv_data;
74
75 if (avctx->channels < 1 || avctx->channels > 2) {
76 av_log(avctx, AV_LOG_ERROR, "invalid number of channels\n");
77 return AVERROR(EINVAL);
78 }
79 if (avctx->block_align < 1 || avctx->block_align % avctx->channels) {
80 av_log(avctx, AV_LOG_ERROR, "invalid block align\n");
81 return AVERROR(EINVAL);
82 }
83
84 avctx->channel_layout = avctx->channels == 1 ? AV_CH_LAYOUT_MONO :
85 AV_CH_LAYOUT_STEREO;
86
87 if (avctx->bits_per_coded_sample == 16)
88 avctx->sample_fmt = AV_SAMPLE_FMT_S16;
89 else
90 avctx->sample_fmt = AV_SAMPLE_FMT_U8;
91 s->out_bps = av_get_bytes_per_sample(avctx->sample_fmt);
92
93 s->chunk_size = avctx->block_align + avctx->channels * (s->out_bps == 2);
94
95 av_log(avctx, AV_LOG_DEBUG, "%d channels, %d bits/sample, "
96 "block align = %d, sample rate = %d\n",
97 avctx->channels, avctx->bits_per_coded_sample, avctx->block_align,
98 avctx->sample_rate);
99
100 return 0;
101 }
102
103 static void decode_audio_s16(int16_t *out, const uint8_t *buf, int buf_size,
104 int channels)
105 {
106 int ch;
107 const uint8_t *buf_end = buf + buf_size;
108 int predictor[2];
109 int st = channels - 1;
110
111 /* decode initial raw sample */
112 for (ch = 0; ch < channels; ch++) {
113 predictor[ch] = (int16_t)AV_RL16(buf);
114 buf += 2;
115 *out++ = predictor[ch];
116 }
117
118 /* decode DPCM samples */
119 ch = 0;
120 while (buf < buf_end) {
121 uint8_t b = *buf++;
122 if (b & 0x80)
123 predictor[ch] -= vmdaudio_table[b & 0x7F];
124 else
125 predictor[ch] += vmdaudio_table[b];
126 predictor[ch] = av_clip_int16(predictor[ch]);
127 *out++ = predictor[ch];
128 ch ^= st;
129 }
130 }
131
132 static int vmdaudio_decode_frame(AVCodecContext *avctx, void *data,
133 int *got_frame_ptr, AVPacket *avpkt)
134 {
135 AVFrame *frame = data;
136 const uint8_t *buf = avpkt->data;
137 const uint8_t *buf_end;
138 int buf_size = avpkt->size;
139 VmdAudioContext *s = avctx->priv_data;
140 int block_type, silent_chunks, audio_chunks;
141 int ret;
142 uint8_t *output_samples_u8;
143 int16_t *output_samples_s16;
144
145 if (buf_size < 16) {
146 av_log(avctx, AV_LOG_WARNING, "skipping small junk packet\n");
147 *got_frame_ptr = 0;
148 return buf_size;
149 }
150
151 block_type = buf[6];
152 if (block_type < BLOCK_TYPE_AUDIO || block_type > BLOCK_TYPE_SILENCE) {
153 av_log(avctx, AV_LOG_ERROR, "unknown block type: %d\n", block_type);
154 return AVERROR(EINVAL);
155 }
156 buf += 16;
157 buf_size -= 16;
158
159 /* get number of silent chunks */
160 silent_chunks = 0;
161 if (block_type == BLOCK_TYPE_INITIAL) {
162 uint32_t flags;
163 if (buf_size < 4) {
164 av_log(avctx, AV_LOG_ERROR, "packet is too small\n");
165 return AVERROR(EINVAL);
166 }
167 flags = AV_RB32(buf);
168 silent_chunks = av_popcount(flags);
169 buf += 4;
170 buf_size -= 4;
171 } else if (block_type == BLOCK_TYPE_SILENCE) {
172 silent_chunks = 1;
173 buf_size = 0; // should already be zero but set it just to be sure
174 }
175
176 /* ensure output buffer is large enough */
177 audio_chunks = buf_size / s->chunk_size;
178
179 /* drop incomplete chunks */
180 buf_size = audio_chunks * s->chunk_size;
181
182 /* get output buffer */
183 frame->nb_samples = ((silent_chunks + audio_chunks) * avctx->block_align) /
184 avctx->channels;
185 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
186 return ret;
187 output_samples_u8 = frame->data[0];
188 output_samples_s16 = (int16_t *)frame->data[0];
189
190 /* decode silent chunks */
191 if (silent_chunks > 0) {
192 int silent_size = avctx->block_align * silent_chunks;
193 av_assert0(avctx->block_align * silent_chunks <= frame->nb_samples * avctx->channels);
194
195 if (s->out_bps == 2) {
196 memset(output_samples_s16, 0x00, silent_size * 2);
197 output_samples_s16 += silent_size;
198 } else {
199 memset(output_samples_u8, 0x80, silent_size);
200 output_samples_u8 += silent_size;
201 }
202 }
203
204 /* decode audio chunks */
205 if (audio_chunks > 0) {
206 buf_end = buf + buf_size;
207 av_assert0((buf_size & (avctx->channels > 1)) == 0);
208 while (buf_end - buf >= s->chunk_size) {
209 if (s->out_bps == 2) {
210 decode_audio_s16(output_samples_s16, buf, s->chunk_size,
211 avctx->channels);
212 output_samples_s16 += avctx->block_align;
213 } else {
214 memcpy(output_samples_u8, buf, s->chunk_size);
215 output_samples_u8 += avctx->block_align;
216 }
217 buf += s->chunk_size;
218 }
219 }
220
221 *got_frame_ptr = 1;
222
223 return avpkt->size;
224 }
225
226 AVCodec ff_vmdaudio_decoder = {
227 .name = "vmdaudio",
228 .long_name = NULL_IF_CONFIG_SMALL("Sierra VMD audio"),
229 .type = AVMEDIA_TYPE_AUDIO,
230 .id = AV_CODEC_ID_VMDAUDIO,
231 .priv_data_size = sizeof(VmdAudioContext),
232 .init = vmdaudio_decode_init,
233 .decode = vmdaudio_decode_frame,
234 .capabilities = CODEC_CAP_DR1,
235 };